The proposed research is designed to evaluate the efficacy of pemoline, methylphenidate and protriptyline in the treatment of narcolepsy. A double-blind, multiple drug, multiple dose level design will be employed. Ability to remain awake and performance on cognitive and motor tasks will be measured in narcoleptic patients while unmedicated and while treatment with one of the drugs at three different dose levels. A normal control group will be studied four times in manner similar to that used for narcoleptic patients. Control subjects will be told that they are going to be medicated with stimulants, but will actually be given placebo throughout the study. Thus the effects of placebo and repeated measurement will be assessed. The project will accomplish the following: 1) Establish an objective method for assessing a patient's alterness. 2) Determine the relation between perceived somnolence and ability to stay awake and perform. 3) Determine if improvement in subjective alertness, ability to stay awake and performance change in a dose-related manner. 4) Determin the relative effectiveness of three drugs typically used to treat narcolepsy.